var fs = require('fs');
var path = require('path');

 var subDir = process.argv[2];
 var filter = process.argv[3];

fs.readdir('D:\\node_x',function(err,list){
    if(err){
        console.log(err);
    }else{
        console.log(list);
        for(var item of list){
            if(path.extname(item) === '.' + filter){
                console.log(item);
            }
        }
    }
});